Creates a WebUI-based Crostini Upgrader

This time with tools/gritsettings/resource_ids. Why this is not in a PRESUBMIT
for all .grd files is a mystery.

The UI is behind the new crostini-webui-upgrader flag
(currently disabled by default)

The main areas for review are

calamity@:
html/js  - chrome/browser/chromeos/crostini_upgrader/
mojo and webui glue classes - chrome/browser/ui/webui/crostini_upgrader/

davidmunro@
crostini business logic - chrome/browser/chromeos/crostini/

In this CL, the optional container backup stage is stubbed, and will be
in a subsequent CL.

A suite of unit/browser tests are also currently lacking. I intend them for
follow-up CLs.


Bug: 930901
Change-Id: I5dd3f838e144c7f705ef2be1af5ac5f5afdf3f67
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1933583
Commit-Queue: Ken Rockot <[email protected]>
Reviewed-by: Dirk Pranke <[email protected]>
Reviewed-by: Ken Rockot <[email protected]>
Reviewed-by: Sam McNally <[email protected]>
Reviewed-by: calamity <[email protected]>
Auto-Submit: Nicholas Verne <[email protected]>
Cr-Commit-Position: refs/heads/master@{#720697}
31 files changed